The present invention relates to a valve for opening and closing a tubular channel or pipe.
A valve in the form of a rotary slide valve for opening and closing individual intake ducts is known from German Patent Application 43 44 504 A1. The intake ducts are part of an intake manifold arrangement for a multicylinder internal combustion engine, particularly an engine having two rows of cylinders in a V-shaped arrangement. A tubular intake air distributor extends over the entire length of the multicylinder internal combustion engine. Individual ducts lead from this distributor to the cylinders of the two rows of cylinders. This construction is structurally complex and costly to produce. Further shorter individual intake pipes also extend from the intake air distributor and open into the first individual ducts. The second individual intake pipes may be switched by the rotary slide valve, which comprises a switching cylinder arranged in a lengthwise hole and switches the duct length. This switching cylinder has an opening for each individual duct, which may be brought into or out of alignment with the respective second individual duct by rotating the switching cylinder. In order to form a seal between the intake ducts or between neighboring openings, a circumferential groove is arranged on the switching cylinder in which an expanding piston ring is disposed, which presses sealingly against the wall of the lengthwise hole or against the inner wall of the sleeve. The friction, which arises as the switching cylinder is rotated, can be reduced through the use of suitable material pairings. The functional reliability of the switching is significantly impaired as a result of the friction.
Published International Patent Application No. WO 98/42966 discloses a switching cylinder designed particularly for use in an intake pipe system of a multicylinder internal combustion engine. The switching cylinder is used for closing and opening the individual intake pipes. Each individual intake pipe is provided with an associated sealing element, which is attached to the switching cylinder. Each sealing element comprises two, preferably parallel, sealing strips whose ends are connected to radially elastic annular seal elements, whereby the sealing strips press elastically against the intake or outlet opening of each individual intake pipe to the lengthwise hole in which the switching cylinder is received. The sealing elements do improve the seal performance, but this arrangement also fails to achieve friction-free rotation of the switching cylinder.